Yes, I've heard it before, especially from Bill O'Reilly on FoxNews Channel, who also talks about how the Elite Media are so brazenly in the tank for Obama. I've also heard "tank" used as a verb, as in "The stock market tanked," meaning it lost a great deal, i. e., it hit the bottom of the tank.

Regards//Larry

"To preserve liberty, it is essential that the whole body of the people always possess arms, and be taught alike, especially when young, how to use them." -- Attributed to Richard Henry Lee